Spie Press Book

Interferometry can be seen as the stethoscope of the precision optical engineer. This book presents various interferometric developments used in physical, optical, and mechanical engineering during the past half century. It is an expanded translation of one chapter of the German Wirtschaftliche Mikrobearbeitung, also by Langenbeck, published by Carl Hanser Verlag, Munich-Vienna, in 2009. The book is illustrated with many practical examples and photographs that are a direct consequence of the author’s vast experience in the subject. The author provides some little-known testing techniques that could lead to future innovation in interferometric testing, along with occasional "Notes for the practitioner," which give the reader tips for successful implementation of the author’s repertoire of techniques. The text will be of value to anyone interested in learning about interferometric evaluation of small mechanical and optical components.

Book Details

Date Published: 29 May 2014Pages: 258ISBN: 9780819491404Volume: TT94

Table of Contents

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Table of Contents

Preface

1 Known Methods: An Assessment of the State of the Art—Newton and Fizeau

1.1 Introduction

1.2 Limited Use of Newton's Method

1.3 Other Methods of Interferometry

1.3.1 Tolansky: one experimenter's indispensable knowledge

1.4 Desirable Features for Safe, Applicable, and Economic
Interferometry

1.4.1 Commercial coherent white light

1.4.2 Light sources for increased distance from reference to sample

1.5 The Often-Neglected Angle of Light Incident to Work

1.5.1 Selecting only one angle of incidence

1.5.2 Instrumental consequences

1.5.3 The multifunctionality of a prism's hypotenuse: beamsplitter, reference, and obliqueness provider

1.6 Knowing the Angle of Incidence with Respect to the Fringe Equivalent

Preface

With new material added to the English translation of Chapter 7 of the German Wirtschaftliche Mikrobearbeitung (Carl Hanser Verlag, 2009), the author presents developments in physical, optical, and mechanical engineering over the past 60 years. The enduring impetus for this work is owed to the late, great gentleman engineer, Gordon J. Watt, with his assertion that optical wavefronts used in interferometers and the surfaces used to build air bearings are complementary. A foremost example of this statement is the fact that a plano-convex lens is confined by surfaces that are equivalent to those defining the Watt air-bearing spindle. The spindle rotor consists of a truncated hemisphere, rigidly connected to a flat disk.

Soon after the author founded Intop Entwicklungen (Baden-Württemberg, Germany) in 1972, G. J. Watt and the author experienced an explosion of spindle-enabling applications and new machines whose performance relied completely on low-axial-error motion (less than 5 nm) and an angular error motion of less than 0.1 arcsec. The bearing's disk took on multiple integral functions: as a polygon wheel, as a polishing scaife for diamond tools, and as a chuck for thin substrates (memory substrates with memory scaling of 14.5). Interferometers for in-process quality control and final acceptance needed to be developed.

Increased interferometric sensitivity by multiple passes was adopted as a technique for measuring small departures from 90 deg, both for the metrology of corner cubes and for extremely sensitive tilt measurement (one of the three CCR mirrors being the front mirror on a problem spindle's nose). Interferometric techniques that facilitated the assembly of ultraprecision machining and metrology machines (3D orthogonal) were developed.

Likewise, decreasing interferometric sensitivity made possible the inspection of nonspecular surfaces. The cost for quality control of mass-produced components (for example, water faucet ceramic seals) was substantially reduced. The inspection technique being used became the standard for expedient handling of samples with interferometric precision.

This relatively recent development focused on measuring tilt error motions of air-bearing spindles, as is amply covered in this book. Tasks that occur every day in an optical shop—such as centering and homogeneity measurement—are treated extensively.

The author gladly shares his recollections and experience with students, scholars, and peers but also wants to give a warning: dealing with optics every day may turn a profession into an obsession!

The author appreciates SPIE for making this publication possible. He also expresses his warm thanks to Prof. Hans Tiziani for frequent, critical discussions.